S DEPARTMENT OF THE INTERIOR
S GEOLOGICAL SURVEY
ATIONAL WETLANDS RESEARCH CENTER
30 CAJUNDOME BLVD
9FAYETTE LA 70506-31 52
BY
Samuel M. Carney
Washingon, D.C. 1992
U.S. Department of the Interior
U.S. Fish and Wildlife Service
P rocedures have been developed over the past 30 earsf for
managing the take of waterfowl by hunters. Wings of
ducks contributed voluntarily to the U. S. Fish and Wildlife
Service by hunters are examined each year by experts. This
procedure involves the determination of species, sex, and age
of ducks through an examination of these detached wings.
Many persons skilled at examining wings of ducks have
retired in recent years. We became concerned that these skills
might be lost to Jitture generations ij'not properly
documented. Documenting such skills is dificult. Subtle
dzferences in feather color andfeather texture are used to
distinguish young ducks from adult ducks and males from
females. Printed words and pictures have their limitations,
but we hope this publication captures the technique and
preserves it.
/' Director
U.S. Fish and Wildlife Service
Introduction .......................................................... 1
Feather groups of the duck wing ............................ 2
Mallard .................................................................. 5
American black duck ........................................ 1 O
Mottled duck ....................................................... 13
Gadwall .............................................................. 1 6
American wigeon ................................................. 19
Green-winged teal ............................................... 24
Blue-winged and cinnamon teals ......................... 28
Northern shoveler ................................................ 3 1
Northern pintail .................................................. 34
Wood duck .......................................................... 39
Harlequin duck ................................................... 42
Steller's eider ........................................................ 45
Separation of redhead and canvasback ................. 48
Redhead .............................................................. 49
Canvasback. ......................................................... 54
Separation of greater and lesser scaups ................. 59
Greater scaup ....................................................... 59
Lesser scaup ......................................................... 6 5
Ring-necked duck ............................................... 70
Separation of common and
Barrow's goldeneyes ......................................... 75
Common goldeneye .........................................7..5.
Barrow's goldeneye ...........................................-.8. 1
Separation of bufflehead and
hooded merganser .........................................8..6
Bufflehead ........................................................8..7.
Hooded merganser ............................................9..2
Separation of red-breasted and
common mergansers .....................................9..6
Red-breasted merganser ......................................9. 6
Common merganser .......................................... 100
Separation of oldsquaw. black scoter.
and surf scoter .............................................. 0 5
Oldsquaw .......................................................1..0.6
Black scoter ....................................................... 1 0
Surf scoter ......................................................... 114
White-winged scoter ........................................ 118
Common eider ............................................. 122
King eider .......................................................... 127
Ruddy duck ....................................................... 132
Fulvous whistling duck ...................................... 135
Black-bellied whistling duck .............................. 138
Appendix: Key to duck species .......................... 141
T his publication contains procedures used by the
U.S. Fish and Wildlife Service to determine
the species, sex and age composition of the harvest
of North American ducks using detached wings
contributed by hunters. Original studies of the use
of duck wings for this purpose began in 1958 and
were led by the author and A.D. Geis. Others con-tributing
to these studies include R.L. Croft, E.M.
Martin, A.N. Novara, L.D. Schroeder, M.G. Smart,
and M.F. Sorensen. Major suppliers of known-age
specimens include: W. Anderson, R.S. Billard,
A.J.Erskine, D. Hall, A.S. Hawkins, C. Hoffpauir,
L.R. Jahn, R. L. Jessen, F.B. Lee, J.J. Lynch, R.K.
Martinson, D.I? Olson, R.I? Osbolt, C. Ritcey,
R.N. Smith, H.E. Spencer, V.D. Stotts, and J.
Takekawa. R.I. Smith edited the text, A.J. Godin
prepared Figure 2, Larry Ketchum Photography
took the pictures, and R.E. Cummins typed the
manuscript.
The Waterfowl Parts Survey became the means by
which large samples of duck wings were obtained.
This survey became national in scope in 1961.
Collection of goose tails was added to the survey in
1962. Packages of envelopes are mailed to selected
hunters who return wings from shot ducks and tail
feathers from shot geese by mail to collection points
throughout the United States where they are exam-ined
to determine species, sex, and age.
For readers who are interested in more detailed
information on the development and testing of
procedures described in the following pages, copies
of a more technical report, which was prepared by
the author, are available by writing to Waterfowl
Harvest Surveys, U.S. Fish and Wildlife Service,
10800 Laurel-Bowie Road, Laurel, Maryland
20708-3600. That report, titled Observations on
Sexing and Aging Ducks Using Wings, makes several
points that must be understood by anyone who
plans serious use of these techniques. The proce-dures
presented here vary among species in the
degree to which they accurately identify the age and
sex of duck wings. Accuracy varies according to
skills of the observer. Some individuals become
highly skilled after examining large numbers of
duck wings, while other individuals never develop
the ability to detect subtle differences in feather
texture and feather quality with high levels of profi-ciency.
Levels of skill will decline if techniques are
not practiced with regularity.
Terminology related to age must be clarified. An
immature wing possesses one or more characteristics
known to be associated with ducks hatched in the
most recent nesting season. Since the term imma-ture
often refers to maturing processes not related to
plumage, juvenalmight have been more appropri-ate.
Nevertheless, after 30 years of use in this con-text,
introducing another age designation would
serve no purpose. All wings not possessing charac-teristics
associated with the most recent hatch are
classified as adult except those of male
eiders which are identified as being from sub-adults.
To determine the species, age, and sex of ducks
from detached wings, a worker must be familiar
with the various feather groups (Figure 1). The first
step is to determine the species represented. A key
to species is included as an appendix to this publica-tion.
Usually, slight differences in feather shape,
color, pattern, wear, or replacement are sufficient
during the fall and winter to separate immatures
from adults. Age determination is a step-by-step
search for one or more traces of immature plumage.
Wings on which no traces of immaturity can be
found, or in some cases those that have positive
adult characters, are considered to be from adults.
During their first fall and winter immatures of
many of the more common species of ducks molt
certain wing-feather groups located near the body
and replace them with adult-type feathers. Those
feathers that are replaced include the tertials, greater
tertial coverts, post humerals, and scapulars.
Scapulars are of limited use in classifying wings
because most hunters do not include scapulars on
the wings they remove. Tertials, as defined here, are
actually the more proximal secondaries, which are
generally different in size, shape, and color from
their more distal counterparts. These feathers are
often sexually dimorphic and usually molt with
adjacent body feathers. Post humerals are feathers
attached to the humerus. They lie between the
tertials and scapulars. They usually molt with adja-cent
body feathers. Greater coverts are the first row
continued on page 4
FEATHER GROUPS OF THE DUCK WING
REMIGES: (Flight feathers)
Alula: The feathered "thumb" of the bird wing
Primaries: Flight feathers attached to the hand (manus)
Secondaries: Flight feathers attached to the forearm (ulna)
Tertials: Incorrect (morphologically) but used here to designate the more prox-imal
secondaries which are generally different in size, shape, and color
from their more distal counterparts, are often sexually dimorphic, and
usually molt with adjacent body feathers.
Post humerals: Feathers attached to the humerus. They lie between the tertials and
scapulars, usually molting with adjacent body feathers.
Scapulars: Feathers of the humeral (upper arm) feather tract. These lie on either
side of the back and may partially cover a folded wing. They usually
molt with adjacent body feathers. (Not shown)
Axillars: Elongate feathers growing in the "armpit" region and closing the
space between the spread wing and the body
WING COVERTS: (Cover flight feathers)
Greater coverts: The first row of feathers overlying the flight feathers, identified by the
particular feathers they cover as primary, secondary, or tertial coverts.
Tertial coverts: Those greater coverts that overlie the tertials. Designated separately
here because they are sexually dimorphic in adults of several species
and usually molt with the adjacent body feathers.
Middle coverts: The next row of coverts.
Lesser coverts: The next several rows of coverts.
Marginal coverts: An indefinite number of rows anterior to the lesser coverts
2
PRIMARIES
Figure 1. Feather groups of a typical dabbling duck wing
of feathers overlying the flight feathers, identified by both fresh wings and wings with varying degrees of
the particular feathers they cover as primary, sec- stiffness, as they are commonly received through the
ondary, or tertial coverts. Greater tertial coverts are Waterfowl Parts Survey. To ensure uniformity all
those greater coverts that overlie the tertials. They measurements are made using a standardized proce-are
designated separately because they are sexually dure and measuring board (Figure 2). Measure-dimorphic
in adults of several species and often ments are referred to as wing notch-length.
molt with the adjacent body feathers. The degree to Tables have an advantage over keys in that the
which these feathers are replaced is quite variable, color, shape, or texture of a particular group of I
even among closely related species. Southern nest- feathers can be compared on one page across the
ing duck species may initiate upperwing molts in four age and sex categories. Unlike keys, tables do
the fall rather than in the spring. Fall wing molting not lead one directly to the answer. Despite this
occurs among wood ducks, mottled ducks, and limitation, most people prefer tables to keys.
whistling ducks. Such molting reduces the accuracy Therefore, tables are used in this publication to
of immature wing identification in the fall and present information on individual species. Wing
characteristics are not always listed in the same
Male wings on most North American ducks are sequence for each species. They are listed in the
slightly larger than those of females. For a few sequence in which they can be most efficiently used.
species, this difference is large enough to permit A brief narrative, which identifies the most
separation of the sexes using wing measurements. frequently used wing characters in a table, accompa-
The procedure for measuring duck wings applies to nies most tables.
Figure 2. Procedure for measuring wings
4
Place the heel of one hand over the end of measuring board and grasp wing in the area of the radius and ulna.
Pull until wooden block seats tightly into the notch at the bend of the wing. Flatten the leading edge of the wing
and note the length of the wing at the longest primary.
Note: If primary quills are not completely grown, the measurernent is not val~d.
Sex Determination
The white bar anterior to the speculum extends
onto the greater tertial coverts on all female wings
but terminates at the proximal edge of the specu-lum
on nearly all male wings. Approximately 2%-3
percent of males show some white edging on their
tertial coverts. Adult males can be identified because
the white is not continuous with that over the sec-ondaries.
Immature males with white over the ter-tial
coverts are difficult to tell from immature
females. The white bar is the easiest sex character to
use, because of its high degree of reliability and the
fact that it is rarely lost when a wing is detached.
Vermiculated scapulars are found only on males.
Early in the hunting season (September and
October) many males possess barred scapulars
which are remnants of their summer plumage.
Proximal underwing coverts are vermiculated or
flecked on adult and most immature males. These
feathers are barred on females and on a few imma-ture
males.
Age Determination of Males
Immature tertials are often frayed and faded,
usually narrow, and lack the pearly color of adult
tertials. By late November immature tertials are
replaced by first winter tertials, identical in appear-ance
to adult feathers. At the same time, immature
tertial coverts may be replaced by coverts which are
broader, unfrayed, and similar to adult coverts and
thus differ from adjacent immature coverts, which
have not been molted. Many immature males have
light edging on the inner webs of the most distal
primary coverts. Adult males do not show this char-acter.
Middle coverts of immatures are narrower and
more trapezoidal than those of adults. Occasionally,
these feathers on immature males are worn and/or
have light edges. This type of edging does not occur
on the middle coverts of adult males.
Age Determination of Females
Tertials that are frayed and/or faded are remnants
of immature plumage and are found only on imma-ture
ducks. Tertial coverts of immatures are often
frayed, faded, and narrow, and the two most proxi-mal
often lack the white of the speculum bar. As
with males, greater tertial coverts of immatures may
be replaced. Conspicuous light edging on the inner
webs of the four most distal primary coverts is
found only on immatures. Adults may have minute
or no edging on these coverts. ~ i d d l ceo verts of
immatures tend to be narrow and trapezoidal, while
those of adults are broadly rounded.
Scapulars 1 Venniculated o'barred or both / Barred
+ -. - I
Wing
Character
I Proximal Flecked to vermiculated I Barred 1 I
Male 1 Female
Adult 1 Immature / Immature 1 Adult
Tertials
- - - - - -
roiinded;.sotid gray
to brown, no edgtljs
Broad, pearly gray, no
edging, rarely frayed or
faded' May be growing in
October
Primary
coverts
Small, narrow, brownish, often frayed or faded near tips.
Adul type feathers may be growing in December or later
After mol: Similar to adul After mol: Similar to adul
male female
Broadty rounded; brown;
~suaHyw Sth light brown
@iQlng; sometimes no
SiigMfy ttiangukr to W o i d a l ; often frayed or faded;
usually bmwn
No edging
Varies from pearly gray to
brownish, often light edging;
rarely frayed or faded
Ma) have fiie'edging or no Edging varies from
w9
Inner web of four most distal
have llght edg~ngo r no
edging
conspicuous to absent edging I
Inner web of four most distal
wlthout edglng to
conspicuous edging
Innerweb of four most distal
wlth llght edglng or no
edging I
m.; a
IFigur-e 5. Adult hniale rnallrird ~ v i r hu necigid co\.ct-ts
Figure 6. Immature male mallard with immature tertials
Age Determination Sex Determination of Adults
Because wings of the sexes are similar, it is easier Adult male tertials are more than 90 mm. long
to determine the age of black ducks before attempt- from the edge of the longest tertial covert to the
ing to identify their sex. Tertials small, narrow, and tertial tip, and acutely pointed with some pearly
frayed andlor faded near their tips are remnants of color on the outer webs. Tertial coverts have broad
immature plumage. Adult tertials are longer and edging which is pale brown. Middle and lesser
wider and are not frayed or faded. Tertial coverts of coverts are broadly rounded and unfrayed. The
the immature plumage tend to be narrow, some- notch-length of 94 percent of the adult male
what trapezoidal, and frequently frayed andlor known-age specimens was greater than 28 1 mm.
faded. Those of adults are wide, broadly rounded, Adult female tertials are less than 90 mm. from and rarely frayed or faded. During their first fall and the edge of the longest tertial covert to the tertial
winter, a substantial fraction of the immatures may tip, and they are rather bluntly pointed. Pearly color
replace both their immature tertials and tertial generally does not occur on the outer webs. Tertial
coverts with adult-type feathers. Thus, it is impor- coverts have broad edging which is pale brown.
tant to look closely at the middle coverts immedi- Middle and lesser coverts are broadly rounded and
ately anterior to the tertial coverts for indications of unfrayed. The notch length of 94% of adult females
the trapezoidal shape, duller color, and wear that was less than 281 mm.
indicate immaturity. Primary coverts of many Immature tertials less than 88 mm. from the
immatures have light edging on their inner webs. longest covert to the tertial tip are from females and
This type of edging does not occur on adults. longer tertials are from males.
1 Wino 1 Male 1 Female 1
I Y"Y'YY'"' I Adult I Immature I Immature I Adult I
1 After molt: Similar to adult After molt: Similar to adult rounded'arc; not frayed of male female 1 faded 1 Greater 1 Four most distal do not have 1 Four most distal otten (but not always) have light edging on 1 Four most distal do not have I ure 11. Adult female black duck
p n p y3qq spur a~naewwI' ~ ;a1rnS !j
- - 1
Because mottled ducks are southern nesters, most females, but there is considerable overlap. Birds
immatures have replaced both tertials and greater with three or more non-iridescent secondaries are
tertial coverts at the time hunting occurs. Careful virtually all females, but birds with only one or two
scrutiny, however, will usually reveal one or more non-iridescent secondaries may be of either sex.
faded coverts in this area. These are remnants of the The greater tertial coverts of females tend to more
immature plumage. Sexual identification is difficult. heavy edging than those of males, but the two types
Wings of males are generally longer than those of grade together.
Male I Female
, Adult 1 Immature I Immature I Adult
Similar to adult males; lack Similar to aduk females; I Often bluntly pointed;
internal markings oflen internal markings often
r mm.; lack internal
. .- 4
Broadly rounded; edging Usually similar to those of Usually similar to those of Broadly rounded with heavy
varies from broad to narrow adult males; often one or adult females; sometimes tan edging
more narrow and frayed or one or more narrow and
faded fraved or faded
1 Notch-length I 81% > 255 mm. 1 84% > 251 mm. 1 81% < 250 mm. 1 86% < 254 mm. 1
Sex Determination of Adults
Greater, middle, and some lesser coverts of adult
males are mostly either black or cinnamon. On
adult females, black and cinnamon feathers are
much restricted to the posterior three or four rows
of coverts. Tertials of adult males are long, acutely
pointed, silver-gay without edging or tipping.
Those of adult females are much shorter, more
bluntly pointed, and silver-brown with cream col-ored
tips. Greater tertial coverts of adult males are
part black and part gray, rarely with traces of white
tipping. Those of adult females are similar but usu-ally
well tipped with white. Marginal coverts of
adult males are without edging but have arcs of
narrow vermiculation. On adult females, these
feathers are similar to the lesser coverts and ofcen
have edging but may be either plain or with wide
internal bars or arcs. Post humerals of adult females
usually have cream edging at their tips. Those of
other ages and sexes do not have this edging.
Sex Determination of Immatures
Tertials of both sexes are short, bluntly pointed, . .
and ofieti frayed at their tips. They are quite similar
to those of adult females. In late fall, they may be
replaced by sexually dimorphic adult-type tertials.
Greater tertial coverts of both sexes usually appear
part black and part gray and are tipped with cream.
They are narrower and more pointed than those of
adults. Greater, middle, and sbme lesser coverts of
immature males have some black andlor cinnamon
in three or more rows. Immature females usually
have little or no cinnamon color and black is ofien
restricted to two rows of coverts. Some males show
arcs of narrow vermiculation. Both sexes may show
pale barring, which is usually wider on females.
Notch-length measurements are usehl to identify
immatures by sex, as long as the shafts of the pri-mary
feathers have hardened. In 90 percent of the
specimens measured, immature male notch-lengths
were equal to or greater than 255 mm., while those
of immature females were less than 255 mm.
---
-------
Immature Immature 1 -- -
Scapulars v o r b a n e d o r b a t h - - . -- - -- -- . I Barred
Tertials Long, acutely pointed; Small; brownish; bluntly pointed; usually Shorter; bluntly pointed;
silver-gray; without edging;
------ gray-brown with
tips not hayed Or faded cream-colored tips which
are not frayed or faded
Greater tertial Bluntly pointed; outer webs Somewhat pointed; outer webs black; inner webs brown; Broadly rounded; usually
coverts black; inner webs gray, often frayed and faded at tips with white tipping; outer 1 rarely with traces of white webs black or brown; inner
tipping; not frayed or faded k - 7 After molt: Similar to adult After molt: Similar to adult fwaedbesd brown; not frayed or
1 Post 1 Broad, rounded, tips without 1 Narrow; pointed; tips without edaino 1 Broad rounded tips, usuallv 1
1 humerals edaing 1 1 lia- ht eda-ina" . I
h- o.t z n a t h 7 5 e 2 6 2m m.. .. . . I 80% > 255 -mm. .. ( 80#s 255mm. I 9 ~ % c ~ r n m . 1
Adult males have a large white uppenving patch,
long acutely pointed tertials with black outenvebs,
and gray greater tertial coverts that are somewhat
pointed and narrowly white-edged.
Adult females have a sharply defined white
edging on both greater and middle tertial coverts.
Usually the sharp white edging on the middle and
lesser coverts is sufficient to identify adult females,
however, a few are so lightly colored as to resemble
immature males. A carehl check of tertials and
greater tertial coverts will serve to identify them.
Immature males usually have small, brownish
tertials and tertial coverts, but by November these
are often replaced with adult male-type feathers.
The middle and lesser coverts are gray-brown and
indistinctly edged with a lighter gray.
Immature females have small, brownish tertials
and tertial coverts similar to those of immature
males. By the middle of the fall hunting season
these may be replaced with adult female-type feath-ers.
The middle and lesser coverts are brownish
with well-defined pale tan edges. Often the greater
secondary coverts lack most of the black tipping
common to wings of other ages and sexes and their
outer webs are brownish gray to gray-white.
Separation of American wigeon wings from
Eurasian wigeon wings can be accomplished using
the following procedures:
American wigeon
Axillars (if present) entirely white or flecked only
at their tips.
Undenving middle coverts all or nearly all white.
Scapulars of males (if present) are heavily vermic-ulated
with reddish brown.
Eurasian wigeon
Axillars (if present) heavily flecked with gray over
their entire length.
Underwing middle coverts heavily flecked with
gray.
Scapulars of males (if present) are heavily
vermiculated with black and white.
1 Male KYaeter 1 Adult 1 Immature
1 Female
I Immature I ~ d u ~ t I . --
Scapular~ I Vmiculated w barred or both --
I Barred
A.
Underwing Coverts gray, heavily flecked with white Coverts brownish; heavily edged with white to gray
( Occasionally as in females I
Brown with light gray-brown edging; often frayed and faded Dark brown; edged with
After molt: Similar to adult white to form a broadly I narrow white edging After molt: Similar to adult rounded arc
male female
GREEN-WINGEDT EAL
If the scapulars are attached, the presence of one frayed. Adult female-type tertials have cream col-or
more vermiculated feathers indicates that the ored edging. Adult male-type tertials are long, with-wing
is from a male. If none of the scapulars are out edging, or with narrow edging. The presence of
vermiculated, the wing could be that of either a adult-type tertials is not by itself an indication of
male or female. age. Many geen-winged teal molt tertials during
The stripe on the most distal tertial is the most the hunting season. For some of these, it is possible
useful indicator of sex. On the wings of males, this to split incoming pin feathers to see whether the
stripe is black and sharply delineated from the basic new feather is male or female in character. For
feather color. On the wings of females, this stripe is wings with molted tertials, determination of sex is
black to brown, but grades into the basic feather not possible.
color. The sex of approximately half of the imma- Tertial coverts that are long and narrow, showing
ture birds can be identified by measurements. fine, light edging, and a frayed fringe are remnants
Wings 183 mm. or longer are from males and of immature plumage and positively identify the
wings shorter than 175 mm. are from females, but wing as being immature. The tertial stripe may be
sex cannot be determined from measurements used to separate the sexes. Adult female-type tertial
between 176 mm. and 182 mm. A sample of wings coverts are broadly rounded with wide edging that
from Adak Island, Alaska, green-winged teal (con- is cream or brown. Adult male-type tertial coverts
sidered a different subspecies) averaged approxi- are a uniform gray, sometimes with a narrow bu@
mately 5 percent longer than wings collected in the edging, and tapering to a blunt point. Adult-type
lower 48 states. The number of iridescent secon- tertial coverts are not a reliable indicator of age.
daries differs between sexes. Wings having fewer Middle coverts of adult males are smooth and
than four secondaries with completely iridescent without edging. Middle coverts of immatures are
green outer webs are usually from females and rough and may show gray-appearing wear at their
wings with five or more such secondaries are usually edges. Immatures may also possess light edging
from males. Sex cannot be determined in this man- which is more pronounced on females, but may also
ner from wings with four or four and a half irides- be present on males. Broad, rounded middle coverts
cent secondaries. with wide edging are found only on adult females.
Immature tertials are small, narrow, and rather Traces of immature plumage usually remain most
delicate. The tips of these feathers are often badly obvious immediately anterior to the tertial coverts.
Wing Male 1 Female
Character
Adult I Immature 1 Immature I Adult
Tertials Uniform gray; tapering to a Small; narrow; rather delicate tips are often badly frayed; Buff edging including
usually buff edging rounded tips; unfrayed;
longitudinal stripe often
poorly defined along inner
edge; may be brown or
black; stripe sometimes well
defined; may be molting
1 1 ( male 1 female I I
1 Middle and Broadly rounded; no edging; Gray with wear around edges; appear ragged; somewhat Broadly rounded; usually
lesser coverts gray that matches tertial narrow and trapezoidal; late in year contrast to a variable with wide light edgjng but
coverts deoree with new freolaced) oreater coverts sometimes no eda~na
Sex Determination
The speculum of males is a bright iridescent
green and that of females is a dull non-iridescent
green. Rarely, a female may show a trace of irides-cence.
The greater secondary coverts of males
appear entirely white on their outer webs while
those of females are heavily dark spotted and fre-quently
appear more dark than light. A few males
may show some spots in the greater coverts.
Age Determination of Males
Tertials of adults are greenish black, rarely frayed,
andyery long and pointed. They are trimmed with
a very narrow tan edging. Tertials of the immature
plumage have wide edging which is tan and they are
much shorter and more bluntly pointed than those
of adults. They are brownish and often somewhat
frayed and faded at the tips. Adult-type tertials
occur on immatures and are similar to those of
adult males but are usually still growing in
December. Adult and replaced tertial coverts of
immatures are similar, i.e. a dark brownish black
without edging but usually showing a blue wash.
Immature-type tertial coverts are brown, usually
with pronounced edging and tan and usually not
washed with blue.
Age Determination of Females
Tertials of adults are much more bluntly pointed
than are the immature tertials. In addition, imma-ture
tertials frequently become somewhat frayed at
their tips. Tertial coverts of adults are usually
straight sided to a rounded tip, whereas those of
immature birds usually narrow slightly to a rounded
tip that often shows traces of fading. Well propor-tioned
white inverted "V's" generally indicate
adults.
-- --
---
, Immature I Adult
Greater
coverts
Tertial Broadly rounded; dark
coverts brown washed with blue; brown usually with
usually without edging; not pronounced light brown
frayed or faded I female
The presence of white primary shafts separates
shovelers from all other North American ducks. All
birds having specula that are more than half gray or
dull non-iridescent green are females. All males and
a few adult females have iridescent green on more
than half of their secondaries.
Most females show cream edging on the lesser
and middle coverts. This often covers all these
feathers, particularly on adult females. Immature
males may show a few cream colored edges on
feathers near the alula.
The tertials of immature males are brownish and
much frayed, while those of adults and first winter
immatures are greenish black and much longer. The
tertial covcrts of the immature male are brownish
black and often show a frayed fringe. Adult tertial
coverts are blackish, often washed with blue. Both
immature tertids and immature tertial coverts are
usually present during October.
Immature males generally have small dusky spots
on their greater coverts, while adults do not.
The immature tertials of females are similar to
those of immature males. The tertials of adult
females are wider, not frayed, and more heavily
washed with white at the tips.
Male I Female
EFacIer 1 Adul, I Immature 1 Immature I Adult
Smoothly rounded; dark Brown; often much frayed; with trace of light edging Brown; white edging forms
brown to shiny black;
After molt: Similar to adult After molt: Similar to adult smoothly rounded arc
unfrayed
male female
White; dark bases normally White; often with small dark White; about 114 - 112 inch of dark base normally shows
covered by middle coverts spots at tip; about 114 - 112
lnch of dark base normally
shows
31 ' -
Sex Determination one wing in 20 shows faint light edging, but the
The speculum is at least partly iridesceRgreen general aspect of these is such that they can readily
(rarely purple) on males and a dull non-iridescent be identified as adults.
F bronze or rarely non-iridescent green on females. The tertial coverts of the immature plumage have
The underwings of most males are flecked to ver- conspicuous edging which is a light yellowish
miculated; those of a few males and all females are brown. Birds with such wings are immature males.
barred. Male adult and first winter tertials are long Tertial coverts of the adult-type lack edging and are
and gray and the innermost has a wide marginal found on both adult and immature wings. Tertials
black stripe. The tertials of females are shorter and that lack the black edging are immature. It seems
more brownish and lack the black stripe. Immature lilcely that wings with new tertials growing after
tertials of both sexes are similar and somewhat like November are immatures.
those of adult females. Vermiculated scapulars are
found only on males, but unvermiculated sca~ulars Age Determination of Females
may be present on both males and females. The middle coverts of the immature plumage are
Tertials and scapulars are useful for identibing rather narrow and somewhat trapezoidal. Any bar-some
males, but not for separating the sexes in all ring of these feathers is largely made up of triangu-cases.
lar patches at the feather edge. The middle coverts
of adults are broad and rounded and any barring is
Age Determination of Males made up of variable shaped patches recessed from
The most useful character for separating the ages the feather's edge.
is the condition of the middle coverts. These have The tertial coverts of the immature plumage are
light edging on immatures and often appear narrow, very frayed, often poorly edged and individual
and frayed. Some of these feathers persist through- feathers are often long and narrow. The tertial
out the hunting season. On adult males, these coverts of adult-type plumage are not very frayed,
feathers are not frayed and generally plain. About are well rounded, and have conspicuous edging.
Wing Male I Female
Character 1 I Immature I Immature Adult
I Underwing Gray; heavily flecked with white I Alternate brown and white bars
I Tertials I Acutelv oointed: brownish I Brown: most distal with 1 Brown with oale lonaitudinal I Bluntlv oointed: dark brown:
I I surrounding rachis I often frayed 1 frayed 1 brownish longitudinal stripe;
I Middle and I Grav: without edaina: I Grav: liaht brown edaina at Brown with liaht edaina: 1 Brown with liaht edaina:
edging; somewhat 1 from edging; rounded
trapezoidal
Immature
f
Adult
Figure 42. Common middle covert markings of female northern pintail
Sex Determination and extends farther distally than on wings of imma-
The white trailing edge of the secondaries on tures.
females is much wider on the outer webs than on
the inner webs. On males, this white edge is Age Determination of Females
approximately the same width on both webs. On Immature tertials are pale bronze with pointed,
females, the first secondary proximal to these white- usually frayed, tips. Immature tertial coverts are
edged feathers is washed with black on the outer narrow and yellow-geen. Most immatures replace
web. Males have no black on this feather. both tertials and tertial coverts with purplish red
adult-type feathers by late October. Usually, the
Age Determination of Males blue iridescence is confined to two rows of coverts
Immature tertials are pale bronze with pointed, and is restricted to the proximal half of the imma-usually
frayed, tips. Immature tertial coverts are ture wing. Adult coverts are somewhat wider and
narrow and yellow-green. Most immatures replace tend to lie more smoothly on the wing. Dark blue
both tertials and tertial coverts with dark blue usually extends onto the third row of coverts and
adult-type feathers by late October. As the imma- extends farther distally than on the immature
ture middle and lesser coverts are replaced by the coverts.
adult-type plumage, the presence of a few dark blue
feathers among the duller coverts indicates immatu- Note:
rity. Usually, the dark blue does not extend onto the By mid-fall, some immature wood ducks hatched
third row of coverts and is much restricted to the in the southern United States appear to have
area anterior to the ~roximahl alf of the secondaries. replaced all of their immature upper-wing coverts.
Generally, coverts of adults are somewhat wider and Their wings cannot be distinguished from those of
tend to lie more smoothly on the wing and the dark adults.
blue usually extends on to the third row of coverts
1 Male I Female I , ,
blue-black; second most
distal white-edged at itst ip A--fIt-e r molt: Similar to adult LAn-..lf.. ter molt: Similar to adult
rounded tips
1 Other 1 Greater and middle coverts Greater coverts and middle Greater coverts often 1 Greater coverts usually 1 anteriorly over three or more confined to two rows of to two rows of cdverts three or more rows of
rows of coverts coverts nearest secondaries anterior to secondaries coverts
I pa A~J)
IOU pue papunod h~qloo~us
sd!~: 1 ~ 061 6u1peus' y3els
SEPARATIONO F REDHEAD
AND CANVASBACK
Adult male canvasbacks have much more white secondary coverts and secondaries is greater on
on the upper surface of their wings than any other wings of redheads of all age and sex groups than it is
age-sex category of redhead or canvasback. All other on the wings of adult female or immature canvas-canvasbacks
have much darker secondaries than backs of either sex.
those of all redheads. Thus, the contrast between
Immature greater coverts are narrower, squared,
often frayed to a point over the tertials with an
indistinct pale tip over the secondaries. During the
hunting season, immature birds occasionally replace
both their immature tertials and greater tertial
coverts with adult-type feathers. For a given sex,
these new feathers are indistinguishable from those
of adults but differ markedly from other immature
greater and middle coverts which are retained. With
practice, redheads can be aged primarily by the
appearance of their tertial coverts. Several combina-tions
are possible: 1) immature-type tertial coverts
always indicate an immature bird but sex is best
determined from other coverts; 2) adult male or
adult female-type coverts similar to the surrounding
coverts indicate an adult of that sex; 3) adult male
or adult female-type tertial coverts that differ from
the surrounding immature-type coverts indicate the
sex of some immature birds.
1 Wing Male Female Character Adult
I
1 Immature I Immature 1 Adult
Broad, smoothly rounded Appear narrow, and usually have ragged pointed tips Broad, smoothly rounded
and flecked or vermiculated After molt: Similar to adult After molt: Similar to adult
male female
Figure 61. Immature female redhead
SEPARATIONO F GREATER
AND LESSER SCAUPS
A white wing stripe normally extends onto the
primaries on greater scaup but is confined to the
secondaries on lesser scaup. There are exceptions.
The stripes may not conform on a few male lesser
scaup with unusually white wings or female greater
scaup with unusually dark wings.
Approximately 94 percent of scaup wings can be
correctly assigned to species using wing length,
provided the age-sex class of each wing is known.
The following points will identify greater scaup in
each age class: adult males > 213 mm., adult
females > 206 mm., immature males > 209 mm
and immature females > 203 mm. Wings in each
age class that are shorter than these measurements
are, in most cases, lesser scaup.
Because the two species are similar, the following
discussion pertains to both. Scaup differ from most
other species of the same genus in that they rarely
molt tertial coverts during the hunting season
(October-January). Other characteristics useful for
age-sex identification do not vary greatly, and once
a person has learned to recognize them, wings of
scaup are relatively easy to classify. Although charac-teristics
that separate ages and sexes are similar for
both species, they are not identical, and each is
presented in a separate table.
11 wing 1 Male Character / Adult I Immature
I Female 1
1 Immature I Adult I
1 I white near tios. tios oointed fleckina: tiosbointed. usuallv fleckina: tios oointed. usuallv without whiie fleckino 1
Middle and Black; all are well Black to dark brown with Black to dark brown, without Black to dark brown, plain or
lesser vermiculated with white large white flecks to small white flecks; often ragged with very small white flecks
coverts vermiculations recessed 118" and notched at tip concentrated near coverts'
from coverts' edge; often edge; broadly rounded at tip
raaaed and notched at ti0
Wing Male I Female
Character Adult I Immature 1 Immalure 1 Adult
/ ~ c a ~ u l a r s ' Heavily vermiculated; appear Lightly venniculated or flecked with whlte; appear more dark than white
more white than black
I- After molt Similar to adult After molt: No obvious
male chanpe 1 --
Tertials Black, flecked to Black, barely flecked to well Black to very dark brown, Black to very dark brown;
vermiculated with white; tips vermiculated with white; tips without flecks of white; tips without flecks of white; tips
pointed and often drooping usually frayed to sharp point usually frayed to sharp point usually bluntly polnted
Middle and Black; all are well Black with large white flecks Black without white flecks; Tips broadly rounded and
lesser vermiculated with white to small vermiculat~ons often ragged and notched at smooth; coverts black with
coverts recessed 118" from coverts' tip small white flecks
edge; often ragged and concentrated at tips or plain
notched at ti^
Age Determination
Ring-necked duck wings should be examined
under ideal lighting, preferably daylight rather than
artificial light. A high fraction of immatures replace
tertial coverts during the hunting season with shiny
black feathers that differ slightly from the very dark
brown of the other wing coverts. It may be neces-sary
to tilt a wing back and forth to see this differ-ence.
If no difference is apparent and all tertial
coverts are broadly rounded, the wing is from an
adult. If, however, the tertial coverts tend to narrow
toward their tips and/or appear frayed andlor
notched, the wing is from an immature. Many of
the middle and lesser coverts of immatures may also
show notches.
Sex Determination
The sexes of approximately half of each age group
can be identified from wing measurements provided
all primary quills have hardened. Adults with a
notch-length of 196 mm. or more are males and
those with a notch-length of 188 mm. or less are
females. Immatures with wings 194 mm. or longer
are males while those with wings 184 mm. or
shorter are females. There are a few exceptions to
these measurements. There is too much overlap to
permit accurate sex determination of adults with
wings 189- 195 mm. long or immatures with wings
185-193 mm. long using measurements done.
Adult male tertials are shiny, greenish black and
bluntly pointed. The tertials of adult females are
similar but slightly less shiny, greenish brown and
broadly rounded. Males are usually flecked (often
faintly) on the underwing over the radius and ulna.
Females are rarely flecked in this area. All of these
differences are slight and accurate sex determination
is quite difficult. Because some immature males
resemble immature females, sex determination of
immatures is not completely reliable.
Wing Male Female
Character
Adult 1 Immature I Immature 1 Adult
Greater tertial Broadly rounded, dark Dark brown to blackish; usually narrow slightly to ragged tips Broadly rounded, dark '
coverts blackish After molt: Similar to adult After molt: Similar to adult
brown
male female
1 Underwing 1 White flecking present on small coverts near leading edge of Small coverts near leading edge brownish, with white edging,
wing most pronounced near body 1 rarely with trace of white flecklng
Notch-length 1 88% > 193 mm. .- f 8896 r 189 mm. 1 86% < 189 mm. 1 88% c 192 mm.

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S DEPARTMENT OF THE INTERIOR
S GEOLOGICAL SURVEY
ATIONAL WETLANDS RESEARCH CENTER
30 CAJUNDOME BLVD
9FAYETTE LA 70506-31 52
BY
Samuel M. Carney
Washingon, D.C. 1992
U.S. Department of the Interior
U.S. Fish and Wildlife Service
P rocedures have been developed over the past 30 earsf for
managing the take of waterfowl by hunters. Wings of
ducks contributed voluntarily to the U. S. Fish and Wildlife
Service by hunters are examined each year by experts. This
procedure involves the determination of species, sex, and age
of ducks through an examination of these detached wings.
Many persons skilled at examining wings of ducks have
retired in recent years. We became concerned that these skills
might be lost to Jitture generations ij'not properly
documented. Documenting such skills is dificult. Subtle
dzferences in feather color andfeather texture are used to
distinguish young ducks from adult ducks and males from
females. Printed words and pictures have their limitations,
but we hope this publication captures the technique and
preserves it.
/' Director
U.S. Fish and Wildlife Service
Introduction .......................................................... 1
Feather groups of the duck wing ............................ 2
Mallard .................................................................. 5
American black duck ........................................ 1 O
Mottled duck ....................................................... 13
Gadwall .............................................................. 1 6
American wigeon ................................................. 19
Green-winged teal ............................................... 24
Blue-winged and cinnamon teals ......................... 28
Northern shoveler ................................................ 3 1
Northern pintail .................................................. 34
Wood duck .......................................................... 39
Harlequin duck ................................................... 42
Steller's eider ........................................................ 45
Separation of redhead and canvasback ................. 48
Redhead .............................................................. 49
Canvasback. ......................................................... 54
Separation of greater and lesser scaups ................. 59
Greater scaup ....................................................... 59
Lesser scaup ......................................................... 6 5
Ring-necked duck ............................................... 70
Separation of common and
Barrow's goldeneyes ......................................... 75
Common goldeneye .........................................7..5.
Barrow's goldeneye ...........................................-.8. 1
Separation of bufflehead and
hooded merganser .........................................8..6
Bufflehead ........................................................8..7.
Hooded merganser ............................................9..2
Separation of red-breasted and
common mergansers .....................................9..6
Red-breasted merganser ......................................9. 6
Common merganser .......................................... 100
Separation of oldsquaw. black scoter.
and surf scoter .............................................. 0 5
Oldsquaw .......................................................1..0.6
Black scoter ....................................................... 1 0
Surf scoter ......................................................... 114
White-winged scoter ........................................ 118
Common eider ............................................. 122
King eider .......................................................... 127
Ruddy duck ....................................................... 132
Fulvous whistling duck ...................................... 135
Black-bellied whistling duck .............................. 138
Appendix: Key to duck species .......................... 141
T his publication contains procedures used by the
U.S. Fish and Wildlife Service to determine
the species, sex and age composition of the harvest
of North American ducks using detached wings
contributed by hunters. Original studies of the use
of duck wings for this purpose began in 1958 and
were led by the author and A.D. Geis. Others con-tributing
to these studies include R.L. Croft, E.M.
Martin, A.N. Novara, L.D. Schroeder, M.G. Smart,
and M.F. Sorensen. Major suppliers of known-age
specimens include: W. Anderson, R.S. Billard,
A.J.Erskine, D. Hall, A.S. Hawkins, C. Hoffpauir,
L.R. Jahn, R. L. Jessen, F.B. Lee, J.J. Lynch, R.K.
Martinson, D.I? Olson, R.I? Osbolt, C. Ritcey,
R.N. Smith, H.E. Spencer, V.D. Stotts, and J.
Takekawa. R.I. Smith edited the text, A.J. Godin
prepared Figure 2, Larry Ketchum Photography
took the pictures, and R.E. Cummins typed the
manuscript.
The Waterfowl Parts Survey became the means by
which large samples of duck wings were obtained.
This survey became national in scope in 1961.
Collection of goose tails was added to the survey in
1962. Packages of envelopes are mailed to selected
hunters who return wings from shot ducks and tail
feathers from shot geese by mail to collection points
throughout the United States where they are exam-ined
to determine species, sex, and age.
For readers who are interested in more detailed
information on the development and testing of
procedures described in the following pages, copies
of a more technical report, which was prepared by
the author, are available by writing to Waterfowl
Harvest Surveys, U.S. Fish and Wildlife Service,
10800 Laurel-Bowie Road, Laurel, Maryland
20708-3600. That report, titled Observations on
Sexing and Aging Ducks Using Wings, makes several
points that must be understood by anyone who
plans serious use of these techniques. The proce-dures
presented here vary among species in the
degree to which they accurately identify the age and
sex of duck wings. Accuracy varies according to
skills of the observer. Some individuals become
highly skilled after examining large numbers of
duck wings, while other individuals never develop
the ability to detect subtle differences in feather
texture and feather quality with high levels of profi-ciency.
Levels of skill will decline if techniques are
not practiced with regularity.
Terminology related to age must be clarified. An
immature wing possesses one or more characteristics
known to be associated with ducks hatched in the
most recent nesting season. Since the term imma-ture
often refers to maturing processes not related to
plumage, juvenalmight have been more appropri-ate.
Nevertheless, after 30 years of use in this con-text,
introducing another age designation would
serve no purpose. All wings not possessing charac-teristics
associated with the most recent hatch are
classified as adult except those of male
eiders which are identified as being from sub-adults.
To determine the species, age, and sex of ducks
from detached wings, a worker must be familiar
with the various feather groups (Figure 1). The first
step is to determine the species represented. A key
to species is included as an appendix to this publica-tion.
Usually, slight differences in feather shape,
color, pattern, wear, or replacement are sufficient
during the fall and winter to separate immatures
from adults. Age determination is a step-by-step
search for one or more traces of immature plumage.
Wings on which no traces of immaturity can be
found, or in some cases those that have positive
adult characters, are considered to be from adults.
During their first fall and winter immatures of
many of the more common species of ducks molt
certain wing-feather groups located near the body
and replace them with adult-type feathers. Those
feathers that are replaced include the tertials, greater
tertial coverts, post humerals, and scapulars.
Scapulars are of limited use in classifying wings
because most hunters do not include scapulars on
the wings they remove. Tertials, as defined here, are
actually the more proximal secondaries, which are
generally different in size, shape, and color from
their more distal counterparts. These feathers are
often sexually dimorphic and usually molt with
adjacent body feathers. Post humerals are feathers
attached to the humerus. They lie between the
tertials and scapulars. They usually molt with adja-cent
body feathers. Greater coverts are the first row
continued on page 4
FEATHER GROUPS OF THE DUCK WING
REMIGES: (Flight feathers)
Alula: The feathered "thumb" of the bird wing
Primaries: Flight feathers attached to the hand (manus)
Secondaries: Flight feathers attached to the forearm (ulna)
Tertials: Incorrect (morphologically) but used here to designate the more prox-imal
secondaries which are generally different in size, shape, and color
from their more distal counterparts, are often sexually dimorphic, and
usually molt with adjacent body feathers.
Post humerals: Feathers attached to the humerus. They lie between the tertials and
scapulars, usually molting with adjacent body feathers.
Scapulars: Feathers of the humeral (upper arm) feather tract. These lie on either
side of the back and may partially cover a folded wing. They usually
molt with adjacent body feathers. (Not shown)
Axillars: Elongate feathers growing in the "armpit" region and closing the
space between the spread wing and the body
WING COVERTS: (Cover flight feathers)
Greater coverts: The first row of feathers overlying the flight feathers, identified by the
particular feathers they cover as primary, secondary, or tertial coverts.
Tertial coverts: Those greater coverts that overlie the tertials. Designated separately
here because they are sexually dimorphic in adults of several species
and usually molt with the adjacent body feathers.
Middle coverts: The next row of coverts.
Lesser coverts: The next several rows of coverts.
Marginal coverts: An indefinite number of rows anterior to the lesser coverts
2
PRIMARIES
Figure 1. Feather groups of a typical dabbling duck wing
of feathers overlying the flight feathers, identified by both fresh wings and wings with varying degrees of
the particular feathers they cover as primary, sec- stiffness, as they are commonly received through the
ondary, or tertial coverts. Greater tertial coverts are Waterfowl Parts Survey. To ensure uniformity all
those greater coverts that overlie the tertials. They measurements are made using a standardized proce-are
designated separately because they are sexually dure and measuring board (Figure 2). Measure-dimorphic
in adults of several species and often ments are referred to as wing notch-length.
molt with the adjacent body feathers. The degree to Tables have an advantage over keys in that the
which these feathers are replaced is quite variable, color, shape, or texture of a particular group of I
even among closely related species. Southern nest- feathers can be compared on one page across the
ing duck species may initiate upperwing molts in four age and sex categories. Unlike keys, tables do
the fall rather than in the spring. Fall wing molting not lead one directly to the answer. Despite this
occurs among wood ducks, mottled ducks, and limitation, most people prefer tables to keys.
whistling ducks. Such molting reduces the accuracy Therefore, tables are used in this publication to
of immature wing identification in the fall and present information on individual species. Wing
characteristics are not always listed in the same
Male wings on most North American ducks are sequence for each species. They are listed in the
slightly larger than those of females. For a few sequence in which they can be most efficiently used.
species, this difference is large enough to permit A brief narrative, which identifies the most
separation of the sexes using wing measurements. frequently used wing characters in a table, accompa-
The procedure for measuring duck wings applies to nies most tables.
Figure 2. Procedure for measuring wings
4
Place the heel of one hand over the end of measuring board and grasp wing in the area of the radius and ulna.
Pull until wooden block seats tightly into the notch at the bend of the wing. Flatten the leading edge of the wing
and note the length of the wing at the longest primary.
Note: If primary quills are not completely grown, the measurernent is not val~d.
Sex Determination
The white bar anterior to the speculum extends
onto the greater tertial coverts on all female wings
but terminates at the proximal edge of the specu-lum
on nearly all male wings. Approximately 2%-3
percent of males show some white edging on their
tertial coverts. Adult males can be identified because
the white is not continuous with that over the sec-ondaries.
Immature males with white over the ter-tial
coverts are difficult to tell from immature
females. The white bar is the easiest sex character to
use, because of its high degree of reliability and the
fact that it is rarely lost when a wing is detached.
Vermiculated scapulars are found only on males.
Early in the hunting season (September and
October) many males possess barred scapulars
which are remnants of their summer plumage.
Proximal underwing coverts are vermiculated or
flecked on adult and most immature males. These
feathers are barred on females and on a few imma-ture
males.
Age Determination of Males
Immature tertials are often frayed and faded,
usually narrow, and lack the pearly color of adult
tertials. By late November immature tertials are
replaced by first winter tertials, identical in appear-ance
to adult feathers. At the same time, immature
tertial coverts may be replaced by coverts which are
broader, unfrayed, and similar to adult coverts and
thus differ from adjacent immature coverts, which
have not been molted. Many immature males have
light edging on the inner webs of the most distal
primary coverts. Adult males do not show this char-acter.
Middle coverts of immatures are narrower and
more trapezoidal than those of adults. Occasionally,
these feathers on immature males are worn and/or
have light edges. This type of edging does not occur
on the middle coverts of adult males.
Age Determination of Females
Tertials that are frayed and/or faded are remnants
of immature plumage and are found only on imma-ture
ducks. Tertial coverts of immatures are often
frayed, faded, and narrow, and the two most proxi-mal
often lack the white of the speculum bar. As
with males, greater tertial coverts of immatures may
be replaced. Conspicuous light edging on the inner
webs of the four most distal primary coverts is
found only on immatures. Adults may have minute
or no edging on these coverts. ~ i d d l ceo verts of
immatures tend to be narrow and trapezoidal, while
those of adults are broadly rounded.
Scapulars 1 Venniculated o'barred or both / Barred
+ -. - I
Wing
Character
I Proximal Flecked to vermiculated I Barred 1 I
Male 1 Female
Adult 1 Immature / Immature 1 Adult
Tertials
- - - - - -
roiinded;.sotid gray
to brown, no edgtljs
Broad, pearly gray, no
edging, rarely frayed or
faded' May be growing in
October
Primary
coverts
Small, narrow, brownish, often frayed or faded near tips.
Adul type feathers may be growing in December or later
After mol: Similar to adul After mol: Similar to adul
male female
Broadty rounded; brown;
~suaHyw Sth light brown
@iQlng; sometimes no
SiigMfy ttiangukr to W o i d a l ; often frayed or faded;
usually bmwn
No edging
Varies from pearly gray to
brownish, often light edging;
rarely frayed or faded
Ma) have fiie'edging or no Edging varies from
w9
Inner web of four most distal
have llght edg~ngo r no
edging
conspicuous to absent edging I
Inner web of four most distal
wlthout edglng to
conspicuous edging
Innerweb of four most distal
wlth llght edglng or no
edging I
m.; a
IFigur-e 5. Adult hniale rnallrird ~ v i r hu necigid co\.ct-ts
Figure 6. Immature male mallard with immature tertials
Age Determination Sex Determination of Adults
Because wings of the sexes are similar, it is easier Adult male tertials are more than 90 mm. long
to determine the age of black ducks before attempt- from the edge of the longest tertial covert to the
ing to identify their sex. Tertials small, narrow, and tertial tip, and acutely pointed with some pearly
frayed andlor faded near their tips are remnants of color on the outer webs. Tertial coverts have broad
immature plumage. Adult tertials are longer and edging which is pale brown. Middle and lesser
wider and are not frayed or faded. Tertial coverts of coverts are broadly rounded and unfrayed. The
the immature plumage tend to be narrow, some- notch-length of 94 percent of the adult male
what trapezoidal, and frequently frayed andlor known-age specimens was greater than 28 1 mm.
faded. Those of adults are wide, broadly rounded, Adult female tertials are less than 90 mm. from and rarely frayed or faded. During their first fall and the edge of the longest tertial covert to the tertial
winter, a substantial fraction of the immatures may tip, and they are rather bluntly pointed. Pearly color
replace both their immature tertials and tertial generally does not occur on the outer webs. Tertial
coverts with adult-type feathers. Thus, it is impor- coverts have broad edging which is pale brown.
tant to look closely at the middle coverts immedi- Middle and lesser coverts are broadly rounded and
ately anterior to the tertial coverts for indications of unfrayed. The notch length of 94% of adult females
the trapezoidal shape, duller color, and wear that was less than 281 mm.
indicate immaturity. Primary coverts of many Immature tertials less than 88 mm. from the
immatures have light edging on their inner webs. longest covert to the tertial tip are from females and
This type of edging does not occur on adults. longer tertials are from males.
1 Wino 1 Male 1 Female 1
I Y"Y'YY'"' I Adult I Immature I Immature I Adult I
1 After molt: Similar to adult After molt: Similar to adult rounded'arc; not frayed of male female 1 faded 1 Greater 1 Four most distal do not have 1 Four most distal otten (but not always) have light edging on 1 Four most distal do not have I ure 11. Adult female black duck
p n p y3qq spur a~naewwI' ~ ;a1rnS !j
- - 1
Because mottled ducks are southern nesters, most females, but there is considerable overlap. Birds
immatures have replaced both tertials and greater with three or more non-iridescent secondaries are
tertial coverts at the time hunting occurs. Careful virtually all females, but birds with only one or two
scrutiny, however, will usually reveal one or more non-iridescent secondaries may be of either sex.
faded coverts in this area. These are remnants of the The greater tertial coverts of females tend to more
immature plumage. Sexual identification is difficult. heavy edging than those of males, but the two types
Wings of males are generally longer than those of grade together.
Male I Female
, Adult 1 Immature I Immature I Adult
Similar to adult males; lack Similar to aduk females; I Often bluntly pointed;
internal markings oflen internal markings often
r mm.; lack internal
. .- 4
Broadly rounded; edging Usually similar to those of Usually similar to those of Broadly rounded with heavy
varies from broad to narrow adult males; often one or adult females; sometimes tan edging
more narrow and frayed or one or more narrow and
faded fraved or faded
1 Notch-length I 81% > 255 mm. 1 84% > 251 mm. 1 81% < 250 mm. 1 86% < 254 mm. 1
Sex Determination of Adults
Greater, middle, and some lesser coverts of adult
males are mostly either black or cinnamon. On
adult females, black and cinnamon feathers are
much restricted to the posterior three or four rows
of coverts. Tertials of adult males are long, acutely
pointed, silver-gay without edging or tipping.
Those of adult females are much shorter, more
bluntly pointed, and silver-brown with cream col-ored
tips. Greater tertial coverts of adult males are
part black and part gray, rarely with traces of white
tipping. Those of adult females are similar but usu-ally
well tipped with white. Marginal coverts of
adult males are without edging but have arcs of
narrow vermiculation. On adult females, these
feathers are similar to the lesser coverts and ofcen
have edging but may be either plain or with wide
internal bars or arcs. Post humerals of adult females
usually have cream edging at their tips. Those of
other ages and sexes do not have this edging.
Sex Determination of Immatures
Tertials of both sexes are short, bluntly pointed, . .
and ofieti frayed at their tips. They are quite similar
to those of adult females. In late fall, they may be
replaced by sexually dimorphic adult-type tertials.
Greater tertial coverts of both sexes usually appear
part black and part gray and are tipped with cream.
They are narrower and more pointed than those of
adults. Greater, middle, and sbme lesser coverts of
immature males have some black andlor cinnamon
in three or more rows. Immature females usually
have little or no cinnamon color and black is ofien
restricted to two rows of coverts. Some males show
arcs of narrow vermiculation. Both sexes may show
pale barring, which is usually wider on females.
Notch-length measurements are usehl to identify
immatures by sex, as long as the shafts of the pri-mary
feathers have hardened. In 90 percent of the
specimens measured, immature male notch-lengths
were equal to or greater than 255 mm., while those
of immature females were less than 255 mm.
---
-------
Immature Immature 1 -- -
Scapulars v o r b a n e d o r b a t h - - . -- - -- -- . I Barred
Tertials Long, acutely pointed; Small; brownish; bluntly pointed; usually Shorter; bluntly pointed;
silver-gray; without edging;
------ gray-brown with
tips not hayed Or faded cream-colored tips which
are not frayed or faded
Greater tertial Bluntly pointed; outer webs Somewhat pointed; outer webs black; inner webs brown; Broadly rounded; usually
coverts black; inner webs gray, often frayed and faded at tips with white tipping; outer 1 rarely with traces of white webs black or brown; inner
tipping; not frayed or faded k - 7 After molt: Similar to adult After molt: Similar to adult fwaedbesd brown; not frayed or
1 Post 1 Broad, rounded, tips without 1 Narrow; pointed; tips without edaino 1 Broad rounded tips, usuallv 1
1 humerals edaing 1 1 lia- ht eda-ina" . I
h- o.t z n a t h 7 5 e 2 6 2m m.. .. . . I 80% > 255 -mm. .. ( 80#s 255mm. I 9 ~ % c ~ r n m . 1
Adult males have a large white uppenving patch,
long acutely pointed tertials with black outenvebs,
and gray greater tertial coverts that are somewhat
pointed and narrowly white-edged.
Adult females have a sharply defined white
edging on both greater and middle tertial coverts.
Usually the sharp white edging on the middle and
lesser coverts is sufficient to identify adult females,
however, a few are so lightly colored as to resemble
immature males. A carehl check of tertials and
greater tertial coverts will serve to identify them.
Immature males usually have small, brownish
tertials and tertial coverts, but by November these
are often replaced with adult male-type feathers.
The middle and lesser coverts are gray-brown and
indistinctly edged with a lighter gray.
Immature females have small, brownish tertials
and tertial coverts similar to those of immature
males. By the middle of the fall hunting season
these may be replaced with adult female-type feath-ers.
The middle and lesser coverts are brownish
with well-defined pale tan edges. Often the greater
secondary coverts lack most of the black tipping
common to wings of other ages and sexes and their
outer webs are brownish gray to gray-white.
Separation of American wigeon wings from
Eurasian wigeon wings can be accomplished using
the following procedures:
American wigeon
Axillars (if present) entirely white or flecked only
at their tips.
Undenving middle coverts all or nearly all white.
Scapulars of males (if present) are heavily vermic-ulated
with reddish brown.
Eurasian wigeon
Axillars (if present) heavily flecked with gray over
their entire length.
Underwing middle coverts heavily flecked with
gray.
Scapulars of males (if present) are heavily
vermiculated with black and white.
1 Male KYaeter 1 Adult 1 Immature
1 Female
I Immature I ~ d u ~ t I . --
Scapular~ I Vmiculated w barred or both --
I Barred
A.
Underwing Coverts gray, heavily flecked with white Coverts brownish; heavily edged with white to gray
( Occasionally as in females I
Brown with light gray-brown edging; often frayed and faded Dark brown; edged with
After molt: Similar to adult white to form a broadly I narrow white edging After molt: Similar to adult rounded arc
male female
GREEN-WINGEDT EAL
If the scapulars are attached, the presence of one frayed. Adult female-type tertials have cream col-or
more vermiculated feathers indicates that the ored edging. Adult male-type tertials are long, with-wing
is from a male. If none of the scapulars are out edging, or with narrow edging. The presence of
vermiculated, the wing could be that of either a adult-type tertials is not by itself an indication of
male or female. age. Many geen-winged teal molt tertials during
The stripe on the most distal tertial is the most the hunting season. For some of these, it is possible
useful indicator of sex. On the wings of males, this to split incoming pin feathers to see whether the
stripe is black and sharply delineated from the basic new feather is male or female in character. For
feather color. On the wings of females, this stripe is wings with molted tertials, determination of sex is
black to brown, but grades into the basic feather not possible.
color. The sex of approximately half of the imma- Tertial coverts that are long and narrow, showing
ture birds can be identified by measurements. fine, light edging, and a frayed fringe are remnants
Wings 183 mm. or longer are from males and of immature plumage and positively identify the
wings shorter than 175 mm. are from females, but wing as being immature. The tertial stripe may be
sex cannot be determined from measurements used to separate the sexes. Adult female-type tertial
between 176 mm. and 182 mm. A sample of wings coverts are broadly rounded with wide edging that
from Adak Island, Alaska, green-winged teal (con- is cream or brown. Adult male-type tertial coverts
sidered a different subspecies) averaged approxi- are a uniform gray, sometimes with a narrow bu@
mately 5 percent longer than wings collected in the edging, and tapering to a blunt point. Adult-type
lower 48 states. The number of iridescent secon- tertial coverts are not a reliable indicator of age.
daries differs between sexes. Wings having fewer Middle coverts of adult males are smooth and
than four secondaries with completely iridescent without edging. Middle coverts of immatures are
green outer webs are usually from females and rough and may show gray-appearing wear at their
wings with five or more such secondaries are usually edges. Immatures may also possess light edging
from males. Sex cannot be determined in this man- which is more pronounced on females, but may also
ner from wings with four or four and a half irides- be present on males. Broad, rounded middle coverts
cent secondaries. with wide edging are found only on adult females.
Immature tertials are small, narrow, and rather Traces of immature plumage usually remain most
delicate. The tips of these feathers are often badly obvious immediately anterior to the tertial coverts.
Wing Male 1 Female
Character
Adult I Immature 1 Immature I Adult
Tertials Uniform gray; tapering to a Small; narrow; rather delicate tips are often badly frayed; Buff edging including
usually buff edging rounded tips; unfrayed;
longitudinal stripe often
poorly defined along inner
edge; may be brown or
black; stripe sometimes well
defined; may be molting
1 1 ( male 1 female I I
1 Middle and Broadly rounded; no edging; Gray with wear around edges; appear ragged; somewhat Broadly rounded; usually
lesser coverts gray that matches tertial narrow and trapezoidal; late in year contrast to a variable with wide light edgjng but
coverts deoree with new freolaced) oreater coverts sometimes no eda~na
Sex Determination
The speculum of males is a bright iridescent
green and that of females is a dull non-iridescent
green. Rarely, a female may show a trace of irides-cence.
The greater secondary coverts of males
appear entirely white on their outer webs while
those of females are heavily dark spotted and fre-quently
appear more dark than light. A few males
may show some spots in the greater coverts.
Age Determination of Males
Tertials of adults are greenish black, rarely frayed,
andyery long and pointed. They are trimmed with
a very narrow tan edging. Tertials of the immature
plumage have wide edging which is tan and they are
much shorter and more bluntly pointed than those
of adults. They are brownish and often somewhat
frayed and faded at the tips. Adult-type tertials
occur on immatures and are similar to those of
adult males but are usually still growing in
December. Adult and replaced tertial coverts of
immatures are similar, i.e. a dark brownish black
without edging but usually showing a blue wash.
Immature-type tertial coverts are brown, usually
with pronounced edging and tan and usually not
washed with blue.
Age Determination of Females
Tertials of adults are much more bluntly pointed
than are the immature tertials. In addition, imma-ture
tertials frequently become somewhat frayed at
their tips. Tertial coverts of adults are usually
straight sided to a rounded tip, whereas those of
immature birds usually narrow slightly to a rounded
tip that often shows traces of fading. Well propor-tioned
white inverted "V's" generally indicate
adults.
-- --
---
, Immature I Adult
Greater
coverts
Tertial Broadly rounded; dark
coverts brown washed with blue; brown usually with
usually without edging; not pronounced light brown
frayed or faded I female
The presence of white primary shafts separates
shovelers from all other North American ducks. All
birds having specula that are more than half gray or
dull non-iridescent green are females. All males and
a few adult females have iridescent green on more
than half of their secondaries.
Most females show cream edging on the lesser
and middle coverts. This often covers all these
feathers, particularly on adult females. Immature
males may show a few cream colored edges on
feathers near the alula.
The tertials of immature males are brownish and
much frayed, while those of adults and first winter
immatures are greenish black and much longer. The
tertial covcrts of the immature male are brownish
black and often show a frayed fringe. Adult tertial
coverts are blackish, often washed with blue. Both
immature tertids and immature tertial coverts are
usually present during October.
Immature males generally have small dusky spots
on their greater coverts, while adults do not.
The immature tertials of females are similar to
those of immature males. The tertials of adult
females are wider, not frayed, and more heavily
washed with white at the tips.
Male I Female
EFacIer 1 Adul, I Immature 1 Immature I Adult
Smoothly rounded; dark Brown; often much frayed; with trace of light edging Brown; white edging forms
brown to shiny black;
After molt: Similar to adult After molt: Similar to adult smoothly rounded arc
unfrayed
male female
White; dark bases normally White; often with small dark White; about 114 - 112 inch of dark base normally shows
covered by middle coverts spots at tip; about 114 - 112
lnch of dark base normally
shows
31 ' -
Sex Determination one wing in 20 shows faint light edging, but the
The speculum is at least partly iridesceRgreen general aspect of these is such that they can readily
(rarely purple) on males and a dull non-iridescent be identified as adults.
F bronze or rarely non-iridescent green on females. The tertial coverts of the immature plumage have
The underwings of most males are flecked to ver- conspicuous edging which is a light yellowish
miculated; those of a few males and all females are brown. Birds with such wings are immature males.
barred. Male adult and first winter tertials are long Tertial coverts of the adult-type lack edging and are
and gray and the innermost has a wide marginal found on both adult and immature wings. Tertials
black stripe. The tertials of females are shorter and that lack the black edging are immature. It seems
more brownish and lack the black stripe. Immature lilcely that wings with new tertials growing after
tertials of both sexes are similar and somewhat like November are immatures.
those of adult females. Vermiculated scapulars are
found only on males, but unvermiculated sca~ulars Age Determination of Females
may be present on both males and females. The middle coverts of the immature plumage are
Tertials and scapulars are useful for identibing rather narrow and somewhat trapezoidal. Any bar-some
males, but not for separating the sexes in all ring of these feathers is largely made up of triangu-cases.
lar patches at the feather edge. The middle coverts
of adults are broad and rounded and any barring is
Age Determination of Males made up of variable shaped patches recessed from
The most useful character for separating the ages the feather's edge.
is the condition of the middle coverts. These have The tertial coverts of the immature plumage are
light edging on immatures and often appear narrow, very frayed, often poorly edged and individual
and frayed. Some of these feathers persist through- feathers are often long and narrow. The tertial
out the hunting season. On adult males, these coverts of adult-type plumage are not very frayed,
feathers are not frayed and generally plain. About are well rounded, and have conspicuous edging.
Wing Male I Female
Character 1 I Immature I Immature Adult
I Underwing Gray; heavily flecked with white I Alternate brown and white bars
I Tertials I Acutelv oointed: brownish I Brown: most distal with 1 Brown with oale lonaitudinal I Bluntlv oointed: dark brown:
I I surrounding rachis I often frayed 1 frayed 1 brownish longitudinal stripe;
I Middle and I Grav: without edaina: I Grav: liaht brown edaina at Brown with liaht edaina: 1 Brown with liaht edaina:
edging; somewhat 1 from edging; rounded
trapezoidal
Immature
f
Adult
Figure 42. Common middle covert markings of female northern pintail
Sex Determination and extends farther distally than on wings of imma-
The white trailing edge of the secondaries on tures.
females is much wider on the outer webs than on
the inner webs. On males, this white edge is Age Determination of Females
approximately the same width on both webs. On Immature tertials are pale bronze with pointed,
females, the first secondary proximal to these white- usually frayed, tips. Immature tertial coverts are
edged feathers is washed with black on the outer narrow and yellow-geen. Most immatures replace
web. Males have no black on this feather. both tertials and tertial coverts with purplish red
adult-type feathers by late October. Usually, the
Age Determination of Males blue iridescence is confined to two rows of coverts
Immature tertials are pale bronze with pointed, and is restricted to the proximal half of the imma-usually
frayed, tips. Immature tertial coverts are ture wing. Adult coverts are somewhat wider and
narrow and yellow-green. Most immatures replace tend to lie more smoothly on the wing. Dark blue
both tertials and tertial coverts with dark blue usually extends onto the third row of coverts and
adult-type feathers by late October. As the imma- extends farther distally than on the immature
ture middle and lesser coverts are replaced by the coverts.
adult-type plumage, the presence of a few dark blue
feathers among the duller coverts indicates immatu- Note:
rity. Usually, the dark blue does not extend onto the By mid-fall, some immature wood ducks hatched
third row of coverts and is much restricted to the in the southern United States appear to have
area anterior to the ~roximahl alf of the secondaries. replaced all of their immature upper-wing coverts.
Generally, coverts of adults are somewhat wider and Their wings cannot be distinguished from those of
tend to lie more smoothly on the wing and the dark adults.
blue usually extends on to the third row of coverts
1 Male I Female I , ,
blue-black; second most
distal white-edged at itst ip A--fIt-e r molt: Similar to adult LAn-..lf.. ter molt: Similar to adult
rounded tips
1 Other 1 Greater and middle coverts Greater coverts and middle Greater coverts often 1 Greater coverts usually 1 anteriorly over three or more confined to two rows of to two rows of cdverts three or more rows of
rows of coverts coverts nearest secondaries anterior to secondaries coverts
I pa A~J)
IOU pue papunod h~qloo~us
sd!~: 1 ~ 061 6u1peus' y3els
SEPARATIONO F REDHEAD
AND CANVASBACK
Adult male canvasbacks have much more white secondary coverts and secondaries is greater on
on the upper surface of their wings than any other wings of redheads of all age and sex groups than it is
age-sex category of redhead or canvasback. All other on the wings of adult female or immature canvas-canvasbacks
have much darker secondaries than backs of either sex.
those of all redheads. Thus, the contrast between
Immature greater coverts are narrower, squared,
often frayed to a point over the tertials with an
indistinct pale tip over the secondaries. During the
hunting season, immature birds occasionally replace
both their immature tertials and greater tertial
coverts with adult-type feathers. For a given sex,
these new feathers are indistinguishable from those
of adults but differ markedly from other immature
greater and middle coverts which are retained. With
practice, redheads can be aged primarily by the
appearance of their tertial coverts. Several combina-tions
are possible: 1) immature-type tertial coverts
always indicate an immature bird but sex is best
determined from other coverts; 2) adult male or
adult female-type coverts similar to the surrounding
coverts indicate an adult of that sex; 3) adult male
or adult female-type tertial coverts that differ from
the surrounding immature-type coverts indicate the
sex of some immature birds.
1 Wing Male Female Character Adult
I
1 Immature I Immature 1 Adult
Broad, smoothly rounded Appear narrow, and usually have ragged pointed tips Broad, smoothly rounded
and flecked or vermiculated After molt: Similar to adult After molt: Similar to adult
male female
Figure 61. Immature female redhead
SEPARATIONO F GREATER
AND LESSER SCAUPS
A white wing stripe normally extends onto the
primaries on greater scaup but is confined to the
secondaries on lesser scaup. There are exceptions.
The stripes may not conform on a few male lesser
scaup with unusually white wings or female greater
scaup with unusually dark wings.
Approximately 94 percent of scaup wings can be
correctly assigned to species using wing length,
provided the age-sex class of each wing is known.
The following points will identify greater scaup in
each age class: adult males > 213 mm., adult
females > 206 mm., immature males > 209 mm
and immature females > 203 mm. Wings in each
age class that are shorter than these measurements
are, in most cases, lesser scaup.
Because the two species are similar, the following
discussion pertains to both. Scaup differ from most
other species of the same genus in that they rarely
molt tertial coverts during the hunting season
(October-January). Other characteristics useful for
age-sex identification do not vary greatly, and once
a person has learned to recognize them, wings of
scaup are relatively easy to classify. Although charac-teristics
that separate ages and sexes are similar for
both species, they are not identical, and each is
presented in a separate table.
11 wing 1 Male Character / Adult I Immature
I Female 1
1 Immature I Adult I
1 I white near tios. tios oointed fleckina: tiosbointed. usuallv fleckina: tios oointed. usuallv without whiie fleckino 1
Middle and Black; all are well Black to dark brown with Black to dark brown, without Black to dark brown, plain or
lesser vermiculated with white large white flecks to small white flecks; often ragged with very small white flecks
coverts vermiculations recessed 118" and notched at tip concentrated near coverts'
from coverts' edge; often edge; broadly rounded at tip
raaaed and notched at ti0
Wing Male I Female
Character Adult I Immature 1 Immalure 1 Adult
/ ~ c a ~ u l a r s ' Heavily vermiculated; appear Lightly venniculated or flecked with whlte; appear more dark than white
more white than black
I- After molt Similar to adult After molt: No obvious
male chanpe 1 --
Tertials Black, flecked to Black, barely flecked to well Black to very dark brown, Black to very dark brown;
vermiculated with white; tips vermiculated with white; tips without flecks of white; tips without flecks of white; tips
pointed and often drooping usually frayed to sharp point usually frayed to sharp point usually bluntly polnted
Middle and Black; all are well Black with large white flecks Black without white flecks; Tips broadly rounded and
lesser vermiculated with white to small vermiculat~ons often ragged and notched at smooth; coverts black with
coverts recessed 118" from coverts' tip small white flecks
edge; often ragged and concentrated at tips or plain
notched at ti^
Age Determination
Ring-necked duck wings should be examined
under ideal lighting, preferably daylight rather than
artificial light. A high fraction of immatures replace
tertial coverts during the hunting season with shiny
black feathers that differ slightly from the very dark
brown of the other wing coverts. It may be neces-sary
to tilt a wing back and forth to see this differ-ence.
If no difference is apparent and all tertial
coverts are broadly rounded, the wing is from an
adult. If, however, the tertial coverts tend to narrow
toward their tips and/or appear frayed andlor
notched, the wing is from an immature. Many of
the middle and lesser coverts of immatures may also
show notches.
Sex Determination
The sexes of approximately half of each age group
can be identified from wing measurements provided
all primary quills have hardened. Adults with a
notch-length of 196 mm. or more are males and
those with a notch-length of 188 mm. or less are
females. Immatures with wings 194 mm. or longer
are males while those with wings 184 mm. or
shorter are females. There are a few exceptions to
these measurements. There is too much overlap to
permit accurate sex determination of adults with
wings 189- 195 mm. long or immatures with wings
185-193 mm. long using measurements done.
Adult male tertials are shiny, greenish black and
bluntly pointed. The tertials of adult females are
similar but slightly less shiny, greenish brown and
broadly rounded. Males are usually flecked (often
faintly) on the underwing over the radius and ulna.
Females are rarely flecked in this area. All of these
differences are slight and accurate sex determination
is quite difficult. Because some immature males
resemble immature females, sex determination of
immatures is not completely reliable.
Wing Male Female
Character
Adult 1 Immature I Immature 1 Adult
Greater tertial Broadly rounded, dark Dark brown to blackish; usually narrow slightly to ragged tips Broadly rounded, dark '
coverts blackish After molt: Similar to adult After molt: Similar to adult
brown
male female
1 Underwing 1 White flecking present on small coverts near leading edge of Small coverts near leading edge brownish, with white edging,
wing most pronounced near body 1 rarely with trace of white flecklng
Notch-length 1 88% > 193 mm. .- f 8896 r 189 mm. 1 86% < 189 mm. 1 88% c 192 mm.